From: Adam Jackson ajax@redhat.com

This is about as minimal of a virtual GEM service as possible. My plan is to use this with non-native-3D hardware for buffer sharing between X and DRI.

The current drisw winsys assumes an unmodified X server, which means it's hopelessly inefficient for both the push direction of SwapBuffers/ DrawPixels and the pull direction of GLX_EXT_texture_from_pixmap. I'm still working through the details of what the xserver support will look like, but in broad strokes it's "use vgem for CreatePixmap and optionally the shadowfb".

Obviously alpha quality, mostly looking for feedback on the approach or any glaring bugs. Eventually I'd like to see solutions for sharing gem objects between drm devices and/or the dma_buf API, but that's a ways down the road.

Signed-off-by: Adam Jackson ajax@redhat.com --- drivers/gpu/drm/Kconfig | 8 ++ drivers/gpu/drm/Makefile | 1 + drivers/gpu/drm/vgem/Makefile | 4 + drivers/gpu/drm/vgem/vgem_drv.c | 262 +++++++++++++++++++++++++++++++++++++++ include/drm/vgem_drm.h | 51 ++++++++ 5 files changed, 326 insertions(+), 0 deletions(-) create mode 100644 drivers/gpu/drm/vgem/Makefile create mode 100644 drivers/gpu/drm/vgem/vgem_drv.c create mode 100644 include/drm/vgem_drm.h

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig index 2418429..566c468 100644 --- a/drivers/gpu/drm/Kconfig +++ b/drivers/gpu/drm/Kconfig @@ -159,6 +159,14 @@ config DRM_SAVAGE Choose this option if you have a Savage3D/4/SuperSavage/Pro/Twister chipset. If M is selected the module will be called savage.

+config DRM_VGEM + tristate "Virtual GEM provider" + depends on DRM + help + Choose this option to get a virtual graphics memory manager, + as used by Mesa's software renderer for enhanced performance. + If M is selected the module will be called vgem. + source "drivers/gpu/drm/exynos/Kconfig"

source "drivers/gpu/drm/vmwgfx/Kconfig" diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile index 0cde1b8..021bf8a 100644 --- a/drivers/gpu/drm/Makefile +++ b/drivers/gpu/drm/Makefile @@ -34,6 +34,7 @@ obj-$(CONFIG_DRM_SIS) += sis/ obj-$(CONFIG_DRM_SAVAGE)+= savage/ obj-$(CONFIG_DRM_VMWGFX)+= vmwgfx/ obj-$(CONFIG_DRM_VIA) +=via/ +obj-$(CONFIG_DRM_VGEM) += vgem/ obj-$(CONFIG_DRM_NOUVEAU) +=nouveau/ obj-$(CONFIG_DRM_EXYNOS) +=exynos/ obj-$(CONFIG_DRM_GMA500) += gma500/ diff --git a/drivers/gpu/drm/vgem/Makefile b/drivers/gpu/drm/vgem/Makefile new file mode 100644 index 0000000..3f4c7b8 --- /dev/null +++ b/drivers/gpu/drm/vgem/Makefile @@ -0,0 +1,4 @@ +ccflags-y := -Iinclude/drm +vgem-y := vgem_drv.o + +obj-$(CONFIG_DRM_VGEM) += vgem.o diff --git a/drivers/gpu/drm/vgem/vgem_drv.c b/drivers/gpu/drm/vgem/vgem_drv.c new file mode 100644 index 0000000..82c6787 --- /dev/null +++ b/drivers/gpu/drm/vgem/vgem_drv.c @@ -0,0 +1,262 @@ +/* + * Copyright 2011 Red Hat, Inc. + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the "Software") + * to deal in the software without restriction, including without limitation + * on the rights to use, copy, modify, merge, publish, distribute, sub + * license, and/or sell copies of the Software, and to permit persons to whom + * them Software is furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice (including the next + * paragraph) shall be included in all copies or substantial portions of the + * Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTIBILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES, OR OTHER LIABILITY, WHETHER + * IN AN ACTION OF CONTRACT, TORT, OR OTHERWISE, ARISING FROM, OUT OF OR IN + * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. + * + * Authors: + * Adam Jackson ajax@redhat.com + */ + +/** + * This is vgem, a (non-hardware-backed) GEM service. This is used by Mesa's + * software renderer and the X server for efficient buffer sharing. + */ + +#include "drmP.h" +#include "drm.h" +#include "vgem_drm.h" +#include <linux/module.h> +#include <linux/ramfs.h> + +#define DRIVER_NAME "vgem" +#define DRIVER_DESC "Virtual GEM provider" +#define DRIVER_DATE "20120112" +#define DRIVER_MAJOR 1 +#define DRIVER_MINOR 0 + +static int vgem_load(struct drm_device *dev, unsigned long flags) +{ + return 0; +} + +static int vgem_unload(struct drm_device *dev) +{ + return 0; +} + +static void vgem_preclose(struct drm_device *dev, struct drm_file *file) +{ +} + +static void vgem_lastclose(struct drm_device *dev) +{ +} + +static int vgem_gem_init_object(struct drm_gem_object *obj) +{ + return 0; +} + +static void vgem_gem_free_object(struct drm_gem_object *obj) +{ + if (obj->map_list.map) + drm_gem_free_mmap_offset(obj); + + drm_gem_object_release(obj); +} + +/* XXX I don't think this is ever hit */ +static int vgem_gem_fault(struct vm_area_struct *vma, struct vm_fault *vmf) +{ + BUG(); +} + +static struct vm_operations_struct vgem_gem_vm_ops = { + .fault = vgem_gem_fault, + .open = drm_gem_vm_open, + .close = drm_gem_vm_close, +}; + +/* ioctls */ + +static struct drm_gem_object *vgem_gem_create(struct drm_device *dev, + struct drm_file *file, + unsigned int *handle, + unsigned long size) +{ + int err; + struct drm_gem_object *gem_object; + + size = roundup(size, PAGE_SIZE); + + gem_object = kzalloc(sizeof(*gem_object), GFP_KERNEL); + if (!gem_object) + return ERR_PTR(-ENOMEM); + + if ((err = drm_gem_object_init(dev, gem_object, size))) + goto out; + + if ((err = drm_gem_create_mmap_offset(gem_object))) + goto mmap_out; + + if ((err = drm_gem_handle_create(file, gem_object, handle))) + goto handle_out; + + drm_gem_object_unreference_unlocked(gem_object); + + return gem_object; + +handle_out: + drm_gem_free_mmap_offset(gem_object); + +mmap_out: + drm_gem_object_release(gem_object); + +out: + kfree(gem_object); + + return ERR_PTR(err); +} + +static int vgem_gem_create_ioctl(struct drm_device *dev, void *data, + struct drm_file *file) +{ + struct vgem_gem_create *args = data; + struct drm_gem_object *gem_object; + + gem_object = vgem_gem_create(dev, file, &args->handle, args->size); + + if (IS_ERR(gem_object)) + return PTR_ERR(gem_object); + + return 0; +} + +static int vgem_gem_mmap_ioctl(struct drm_device *dev, void *data, + struct drm_file *file) +{ + struct vgem_gem_mmap *args = data; + struct drm_gem_object *obj; + uintptr_t addr; + + obj = drm_gem_object_lookup(dev, file, args->handle); + if (!obj) + return -ENOENT; + + obj->filp->private_data = obj; + + down_write(&current->mm->mmap_sem); + addr = do_mmap(obj->filp, 0, args->size, PROT_READ | PROT_WRITE, + MAP_SHARED, 0); + up_write(&current->mm->mmap_sem); + + drm_gem_object_unreference_unlocked(obj); + + if (IS_ERR((void *)addr)) + return PTR_ERR((void *)addr); + + args->mapped = addr; + + return 0; +} + +static struct drm_ioctl_desc vgem_ioctls[] = { + DRM_IOCTL_DEF_DRV(VGEM_GEM_CREATE, vgem_gem_create_ioctl, + DRM_UNLOCKED | DRM_AUTH), + DRM_IOCTL_DEF_DRV(VGEM_GEM_MMAP, vgem_gem_mmap_ioctl, + DRM_UNLOCKED | DRM_AUTH), +}; + +static struct drm_driver vgem_driver = { + .driver_features = DRIVER_BUS_PLATFORM | DRIVER_GEM, + .load = vgem_load, + .unload = vgem_unload, + .preclose = vgem_preclose, + .lastclose = vgem_lastclose, + .gem_init_object = vgem_gem_init_object, + .gem_free_object = vgem_gem_free_object, + .gem_vm_ops = &vgem_gem_vm_ops, + .ioctls = vgem_ioctls, + .fops = { + .owner = THIS_MODULE, + .open = drm_open, + .mmap = drm_gem_mmap, + .poll = drm_poll, + .read = drm_read, + .unlocked_ioctl = drm_ioctl, + .release = drm_release, + }, + .name = DRIVER_NAME, + .desc = DRIVER_DESC, + .date = DRIVER_DATE, + .major = DRIVER_MAJOR, + .minor = DRIVER_MINOR, +}; + +static int vgem_platform_probe(struct platform_device *pdev) +{ + vgem_driver.num_ioctls = DRM_ARRAY_SIZE(vgem_ioctls); + + return drm_platform_init(&vgem_driver, pdev); +} + +static int vgem_platform_remove(struct platform_device *pdev) +{ + drm_platform_exit(&vgem_driver, pdev); + + return 0; +} + +static struct platform_driver vgem_platform_driver = { + .probe = vgem_platform_probe, + .remove = __devexit_p(vgem_platform_remove), + .driver = { + .owner = THIS_MODULE, + .name = DRIVER_NAME, + }, +}; + +static struct platform_device *vgem_device; + +static int __init vgem_init(void) +{ + int ret; + + if ((ret = platform_driver_register(&vgem_platform_driver))) + return ret; + + vgem_device = platform_device_alloc("vgem", -1); + if (!vgem_device) { + ret = -ENOMEM; + goto out; + } + + ret = platform_device_add(vgem_device); + if (!ret) + return 0; + +out: + platform_device_put(vgem_device); + platform_driver_unregister(&vgem_platform_driver); + + return ret; +} + +static void __exit vgem_exit(void) +{ + platform_device_unregister(vgem_device); + platform_driver_unregister(&vgem_platform_driver); +} + +module_init(vgem_init); +module_exit(vgem_exit); + +MODULE_AUTHOR("Red Hat, Inc."); +MODULE_DESCRIPTION(DRIVER_DESC); +MODULE_LICENSE("GPL and additional rights"); diff --git a/include/drm/vgem_drm.h b/include/drm/vgem_drm.h new file mode 100644 index 0000000..d73b537 --- /dev/null +++ b/include/drm/vgem_drm.h @@ -0,0 +1,51 @@ +/* + * Copyright 2011 Red Hat, Inc. + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the "Software") + * to deal in the software without restriction, including without limitation + * on the rights to use, copy, modify, merge, publish, distribute, sub + * license, and/or sell copies of the Software, and to permit persons to whom + * them Software is furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice (including the next + * paragraph) shall be included in all copies or substantial portions of the + * Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTIBILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES, OR OTHER LIABILITY, WHETHER + * IN AN ACTION OF CONTRACT, TORT, OR OTHERWISE, ARISING FROM, OUT OF OR IN + * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. + */ + +#ifndef VGEM_DRM_H +#define VGEM_DRM_H + +/* Bare API largely ripped off from exynos driver */ + +struct vgem_gem_create { + unsigned int size; + unsigned int flags; + unsigned int handle; +}; + +struct vgem_gem_mmap { + unsigned int handle; + unsigned int size; + uint64_t mapped; +}; + +#define DRM_VGEM_GEM_CREATE 0x00 +#define DRM_VGEM_GEM_MMAP 0x01 + +#define DRM_IOCTL_VGEM_GEM_CREATE \ + DRM_IOWR(DRM_COMMAND_BASE + DRM_VGEM_GEM_CREATE, \ + struct vgem_gem_create) + +#define DRM_IOCTL_VGEM_GEM_MMAP \ + DRM_IOWR(DRM_COMMAND_BASE + DRM_VGEM_GEM_MMAP, \ + struct vgem_gem_mmap) + +#endif

...or else it just won't build.

Signed-off-by: Ben Widawsky ben@bwidawsk.net --- drivers/gpu/drm/vgem/vgem_drv.c | 20 +++++++++++--------- 1 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/vgem/vgem_drv.c b/drivers/gpu/drm/vgem/vgem_drv.c index 82c6787..3084389 100644 --- a/drivers/gpu/drm/vgem/vgem_drv.c +++ b/drivers/gpu/drm/vgem/vgem_drv.c @@ -173,6 +173,16 @@ static struct drm_ioctl_desc vgem_ioctls[] = { DRM_UNLOCKED | DRM_AUTH), };

+static const struct file_operations vgem_driver_fops = { + .owner = THIS_MODULE, + .open = drm_open, + .mmap = drm_gem_mmap, + .poll = drm_poll, + .read = drm_read, + .unlocked_ioctl = drm_ioctl, + .release = drm_release, +}; + static struct drm_driver vgem_driver = { .driver_features = DRIVER_BUS_PLATFORM | DRIVER_GEM, .load = vgem_load, @@ -183,15 +193,7 @@ static struct drm_driver vgem_driver = { .gem_free_object = vgem_gem_free_object, .gem_vm_ops = &vgem_gem_vm_ops, .ioctls = vgem_ioctls, - .fops = { - .owner = THIS_MODULE, - .open = drm_open, - .mmap = drm_gem_mmap, - .poll = drm_poll, - .read = drm_read, - .unlocked_ioctl = drm_ioctl, - .release = drm_release, - }, + .fops = &vgem_driver_fops, .name = DRIVER_NAME, .desc = DRIVER_DESC, .date = DRIVER_DATE,

Similar to i915, it's nice to be able to query this device uniquely and get some info

Signed-off-by: Ben Widawsky ben@bwidawsk.net --- drivers/gpu/drm/vgem/vgem_drv.c | 29 +++++++++++++++++++++-------- include/drm/vgem_drm.h | 11 +++++++++++ 2 files changed, 32 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/vgem/vgem_drv.c b/drivers/gpu/drm/vgem/vgem_drv.c index d47bd71..7a7a05f 100644 --- a/drivers/gpu/drm/vgem/vgem_drv.c +++ b/drivers/gpu/drm/vgem/vgem_drv.c @@ -158,26 +158,39 @@ static int vgem_gem_mmap_ioctl(struct drm_device *dev, void *data,

obj->filp->private_data = obj;

- down_write(&current->mm->mmap_sem); - addr = do_mmap(obj->filp, 0, args->size, PROT_READ | PROT_WRITE, - MAP_SHARED, 0); - up_write(&current->mm->mmap_sem); + BUG_ON(!obj->map_list.map);

- drm_gem_object_unreference_unlocked(obj); + args->mapped = obj->map_list.hash.key << PAGE_SHIFT;

- if (IS_ERR((void *)addr)) - return PTR_ERR((void *)addr); + return 0; +}

- args->mapped = addr; +static int vgem_gem_getparam_ioctl(struct drm_device *dev, void *data, + struct drm_file *file) +{ + struct vgem_gem_getparam *args = data; + int value=0, ret; + + switch (args->param) { + case VGEM_PARAM_IS_VGEM: + value = 1; + } + + ret = copy_to_user(args->value, &value, sizeof(int)); + if (ret) + return ret;

return 0; }

+ static struct drm_ioctl_desc vgem_ioctls[] = { DRM_IOCTL_DEF_DRV(VGEM_GEM_CREATE, vgem_gem_create_ioctl, DRM_UNLOCKED | DRM_AUTH), DRM_IOCTL_DEF_DRV(VGEM_GEM_MMAP, vgem_gem_mmap_ioctl, DRM_UNLOCKED | DRM_AUTH), + DRM_IOCTL_DEF_DRV(VGEM_GEM_GETPARAM, vgem_gem_getparam_ioctl, + DRM_UNLOCKED), };

static const struct file_operations vgem_driver_fops = { diff --git a/include/drm/vgem_drm.h b/include/drm/vgem_drm.h index d73b537..df83503 100644 --- a/include/drm/vgem_drm.h +++ b/include/drm/vgem_drm.h @@ -37,8 +37,15 @@ struct vgem_gem_mmap { uint64_t mapped; };

+struct vgem_gem_getparam { +#define VGEM_PARAM_IS_VGEM 1 + unsigned int param; + unsigned int *value; +}; + #define DRM_VGEM_GEM_CREATE 0x00 #define DRM_VGEM_GEM_MMAP 0x01 +#define DRM_VGEM_GEM_GETPARAM 0x02

#define DRM_IOCTL_VGEM_GEM_CREATE \ DRM_IOWR(DRM_COMMAND_BASE + DRM_VGEM_GEM_CREATE, \ @@ -48,4 +55,8 @@ struct vgem_gem_mmap { DRM_IOWR(DRM_COMMAND_BASE + DRM_VGEM_GEM_MMAP, \ struct vgem_gem_mmap)

+#define DRM_IOCTL_VGEM_GEM_GETPARAM \ + DRM_IOWR(DRM_COMMAND_BASE + DRM_VGEM_GEM_GETPARAM, \ + struct vgem_gem_getparam) + #endif

Mostly copied from i915 gtt mmaps, this will properly fault in pages as the user tries to use them. The only thing of note are that no prefaulting occurs, so perhaps some kind of madvise will happen later if needed.

The only other thing missing right not is shrinker support, which will come next after I figure out if locking is actually required right now. Hmm, and now that I think about it, mremap, and munmap may not work either.

Signed-off-by: Ben Widawsky ben@bwidawsk.net --- drivers/gpu/drm/vgem/vgem_drv.c | 105 ++++++++++++++++++++++++++++++++++++-- 1 files changed, 99 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/vgem/vgem_drv.c b/drivers/gpu/drm/vgem/vgem_drv.c index 7a7a05f..16f88ee 100644 --- a/drivers/gpu/drm/vgem/vgem_drv.c +++ b/drivers/gpu/drm/vgem/vgem_drv.c @@ -33,6 +33,7 @@ #include "vgem_drm.h" #include <linux/module.h> #include <linux/ramfs.h> +#include <linux/shmem_fs.h>

#define DRIVER_NAME "vgem" #define DRIVER_DESC "Virtual GEM provider" @@ -40,8 +41,11 @@ #define DRIVER_MAJOR 1 #define DRIVER_MINOR 0

+#define to_vgem_bo(x) container_of(x, struct drm_vgem_gem_object, base) + struct drm_vgem_gem_object { struct drm_gem_object base; + struct page **pages; };

static int vgem_load(struct drm_device *dev, unsigned long flags) @@ -67,21 +71,109 @@ static int vgem_gem_init_object(struct drm_gem_object *obj) return 0; }

+static void vgem_gem_put_pages(struct drm_vgem_gem_object *obj) +{ + int num_pages = obj->base.size / PAGE_SIZE; + int i; + + for (i = 0; i < num_pages; i++) { + page_cache_release(obj->pages[i]); + } + + drm_free_large(obj->pages); + obj->pages = NULL; +} + static void vgem_gem_free_object(struct drm_gem_object *obj) { - if (obj->map_list.map) + struct drm_vgem_gem_object *vgem_obj = to_vgem_bo(obj); + + if (obj) drm_gem_free_mmap_offset(obj);

drm_gem_object_release(obj); + + if (vgem_obj->pages) + vgem_gem_put_pages(vgem_obj); + + kfree(vgem_obj); +} + +static int vgem_gem_get_pages(struct drm_vgem_gem_object *obj) +{ + struct address_space *mapping; + gfp_t gfpmask = __GFP_NORETRY | __GFP_NOWARN; + int num_pages, i, ret = 0; + + num_pages = obj->base.size / PAGE_SIZE; + + if (!obj->pages) { + obj->pages = drm_malloc_ab(num_pages, sizeof(struct page *)); + if (obj->pages == NULL) + return -ENOMEM; + } + + mapping = obj->base.filp->f_path.dentry->d_inode->i_mapping; + gfpmask |= mapping_gfp_mask(mapping); + + if (WARN_ON(mapping == NULL)) + return VM_FAULT_SIGBUS; + + for (i = 0; i < num_pages; i++) { + struct page *page; + page = shmem_read_mapping_page_gfp(mapping, i, gfpmask); + if (IS_ERR(page)) { + ret = PTR_ERR(page); + goto err_out; + } + obj->pages[i] = page; + } + + return ret; + +err_out: + while (i--) + page_cache_release(obj->pages[i]); + drm_free_large(obj->pages); + obj->pages = NULL; + return ret; }

-/* XXX I don't think this is ever hit */ static int vgem_gem_fault(struct vm_area_struct *vma, struct vm_fault *vmf) { - BUG(); + struct drm_vgem_gem_object *obj = to_vgem_bo(vma->vm_private_data); + loff_t num_pages; + pgoff_t page_offset; + int ret; + + /* We don't use vmf->pgoff since that has the fake offset */ + page_offset = ((unsigned long)vmf->virtual_address - vma->vm_start) >> + PAGE_SHIFT; + + num_pages = obj->base.size / PAGE_SIZE; + + if (WARN_ON(page_offset > num_pages)) + return VM_FAULT_SIGBUS; + + ret = vgem_gem_get_pages(obj); + if (ret) + return ret; + + ret = vm_insert_page(vma, (unsigned long)vmf->virtual_address, + obj->pages[page_offset]); + + /* Pretty dumb handler for now */ + switch (ret) { + case 0: + case -ERESTARTSYS: + case -EINTR: + return VM_FAULT_NOPAGE; + default: + return VM_FAULT_SIGBUS; + } }

-static struct vm_operations_struct vgem_gem_vm_ops = { +static const struct vm_operations_struct vgem_gem_vm_ops = { .fault = vgem_gem_fault, .open = drm_gem_vm_open, .close = drm_gem_vm_close, @@ -150,7 +242,6 @@ static int vgem_gem_mmap_ioctl(struct drm_device *dev, void *data, { struct vgem_gem_mmap *args = data; struct drm_gem_object *obj; - uintptr_t addr;

obj = drm_gem_object_lookup(dev, file, args->handle); if (!obj) @@ -160,7 +251,9 @@ static int vgem_gem_mmap_ioctl(struct drm_device *dev, void *data,

BUG_ON(!obj->map_list.map);

- args->mapped = obj->map_list.hash.key << PAGE_SHIFT; + args->mapped = (uint64_t)obj->map_list.hash.key << PAGE_SHIFT; + + drm_gem_object_unreference_unlocked(obj);

return 0; }